J Infect Dis. 2013 Oct 15; 208(8):1231-9.

PubMed ID: 23878319

Vaccine-induced gag-specific T cells are associated with reduced viremia after HIV-1 infection

Janes H, Friedrich DP, Krambrink A, Smith RJ, Kallas EG, Horton H, Casimiro DR, Carrington M, Geraghty DE, Gilbert PB, McElrath MJ, Frahm N

The contribution of host T-cell immunity and HLA class I alleles to the control of human immunodeficiency virus (HIV-1) replication in natural infection is widely recognized. We assessed whether vaccine-induced T-cell immunity, or expression of certain HLA alleles, impacted HIV-1 control after infection in the Step MRKAd5/HIV-1 gag/pol/nef study. Vaccine-induced T cells were associated with reduced plasma viremia, with subjects targeting ≥3 gag peptides presenting with half-log lower mean viral loads than subjects without Gag responses. This effect was stronger in participants infected proximal to vaccination and was independent of our observed association of HLA-B*27, -B*57 and -B*58:01 alleles with lower HIV-1 viremia. These findings support the ability of vaccine-induced T-cell responses to influence postinfection outcome and provide a rationale for the generation of T-cell responses by vaccination to reduce viremia if protection from acquisition is not achieved. Clinical trials identifier: NCT00095576.